Hot stamped steel and method for producing the same
US9725782B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 2013 |
| Grant date | Aug 8, 2017 |
| Priority date | — |
| Expiry date | Aug 12, 2033 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12799
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
In a hot stamped steel, when [C] represents an amount of C (mass %), [Si] represents an amount of Si (mass %), and [Mn] represents an amount of Mn (mass %), an expression of 5×[Si]+[Mn])/[C]>10 is satisfied, a metallographic structure includes 80% or more of a martensite in an area fraction, and optionally, further includes one or more of 10% or less of a pearlite in an area fraction, 5% or less of a retained austenite in a volume ratio, 20% or less of a ferrite in an area fraction, and less than 20% of a bainite in an area fraction, TS×λ, which is a product of TS that is a tensile strength and λ that is a hole expansion ratio is 50000 MPa·% or more, and a hardness of the martensite measured with a nanoindenter satisfies H2/H1<1.10 and σHM<20.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.